The present invention relates to a method and to a device for the insertion of a plurality of phase insulators in the cavities of a stator of a dynamo-electric machine.
In the present description and in the following claims, the term "phase insulators" indicates the insulating elements which are used to separate various windings which are engaged in the same cavities of the stator of a dynamo-electric machine. One example of a phase insulator normally used in the art is illustrated in perspective in FIG. 1 of the appended drawings. The insulator is constituted by a sheet of insulating plastics material generally indicated 1 and comprising two end portions 2 and a plurality of bridges 3 which interconnect them and define windows la. FIG. 2 of the appended drawings illustrates in perspective a stator 4 of a dynamo-electric machine provided with a plurality of phase insulators 1 of the type illustrated in FIG. 1. The stator 4 has, in conventional manner, a structure constituted by a pack of laminations having a cylindrical central through aperture 5. A plurality of cavities 6 which are angularly spaced from each other open in the wall of the central aperture 5. Reference numeral 7 generally indicates a primary winding whose turns are inserted in some of the cavities 6 of the stator. A secondary winding (not illustrated) is inserted in the same cavities after the arrangement of phase insulators 1 in the latter. As shown in FIG. 2, the bridges 3 of each phase insulator 1 are inserted each in a corresponding cavity of the stator to separate the primary winding from the secondary winding, while the end portions 2 of each phase insulator 1 project from the ends of the stator and serve to insulate the corresponding parts of the windings.
It is already known in the art (see for example U.S. Pat. No. 4,276,689 and UK Pat. No. 1,445,728) to insert the phase insulators in the cavities of the stator with the aid of devices similar to those used for inserting the prewound coils of the winding in the cavities. More particularly, there is already known from each of the documents mentioned above, a device for inserting a plurality of phase insulators in the cavities of the stator of a dynamo-electric machine, which comprises:
a plurality of guide blades for inserting the phase insulators, disposed circumferentially around a central axis, and
an insertion member which is slidable between the series of guide blades, having a circumferential series of axial grooves in its outer surface in which the various guide blades are engaged, this member being movable from a rest position, in which it allows a plurality of phase insulators to be pre-arranged on the guide blades, to an operative position to cause the phase insulators to slide over the guide blades and the subsequent insertion of these phase insulators within the cavities of a stator arranged at the end of the circumferential series of guide blades.
The prearrangement of the phase insulators above the guide blades so that they can subsequently be inserted in the cavities of the stator must be carried out by the insertion of the bridges 3 of each insulator 1 in the same number of longitudinal spaces defined between adjacent guide blades. With the prior-art devices, this operation had necessarily to be carried out manually to ensure that the insertion occurred correctly without causing deformation or folding of the insulators.